The investigation was conducted by the Medicare Fraud Strike Force, a joint effort of the U.S. Justice Department and the U.S. Department of Health and Human Services, which administers Medicare.

The following Chicago-area residents were charged:

• Ankur Roy, 36, of Miami, Fla., Akash Patel, 33, of Morton Grove, and Dipen Desai, 33, of Chicago, who are described as owners of Selectcare Health Inc., an outpatient respiratory and physical therapy provider with locations in Skokie and Park Ridge.

Messrs. Roy, Patel and Desai are accused of submitting claims to Medicare and Blue Cross & Blue Shield of Illinois for services that could not have been provided, either because a respiratory therapist was not working at the times described or because the services described were in excess of any care scheduled for their patients, federal authorities allege.

Between April 2010 and April 2011, the defendants were paid $2.2 million from Medicare and $321,000 from Blue Cross, according to an indictment. Each man has been charged with six counts of health care fraud.

“Mr. Desai plans a vigorous defense to the case. He recognizes the seriousness of the allegations, and he plans to enter a plea of not guilty at the arraignment,” said his lawyer, Lawrence Hyman of Chicago. The other defendants did not respond to calls for comment.

• Dr. Cecilia Ibrahim, 50, an internist from Frankfort with an office in Flossmoor, has been charged with a single count of health care fraud. She is accused of using a code for a spinal surgery to bill for nonsurgical procedure performed 3,200 times from March 2006 to August 2009, federal authorities allege. She was allegedly improperly paid $300,000 by Medicare and $550,000 by Blue Cross.

• Ellyse Lamon, 30, an Elmhurst resident and account executive for a medical equipment seller, allegedly altered claims in 2010-11 to reflect that a physician had prescribed back braces and nerve stimulation units to patients, even though no prescription had been written.

The claims resulted in $206,000 in improper payments to the company by Medicare, for which Ms. Lamon received increased commissions, federal authorities say. She is charged with one count of health care fraud. Ms. Lamon did not return a message requesting comment.

• Dr. Nalini Ahluwalia, 58, an internist from Burr Ridge, is charged with accepting a $1,000 kickback for referring two patients to a home health care agency in August 2012. The payment was recorded, the government alleges.

An informant told federal investigators that Dr. Ahluwalia previously had accepted kickbacks of $400 or $500 per patient for referrals of Medicare patients. She is charged with one count of violating the anti-kickback law.

Dr. Ahluwalia did not return a message for comment.

• Joseph Dickson, 65, a Lansing-based operator of a medical marketing agency, was charged with accepting $4,200 in kickbacks for referring seven Medicare patients to a home health provider in a recorded October 2012 meeting.

An informant told authorities that Mr. Dickson was a middleman who arranged referrals from a doctor, and that he accepted about $15,000 in kickbacks from 2006 to 2008, federal authorities say. Mr. Dickson, who was charged with one count of violating anti-kickback statutes, could not be reached for comment.

Each charge of health care fraud against Messrs. Roy, Patel and Desai, Dr. Ibrahim and Ms. Lamon carries with it a maximum possible prison sentence of 10 years and a fine of up to $250,000 or twice the loss incurred by the fraud, the government says.

The kickback charges against Dr. Ahluwalia and Mr. Dixon carry a maximum prison sentence of five years and a $250,000 fine, according to the government.